The present invention relates to an indicator device for automobiles which can show locations if there is something wrong with various functions installed through the car, and more particularly to an improved indicator device which can provide information in many different characters within its limited indicating area. For recent years, automatic control systems or automatic monitor systems have been developed and used in various fields such as vehicles. With the introduction of those systems, there arises a need for means by which the status or change of the different operating points of the systems can be provided in visual forms.
It is generally known that characters, symbols or patterns (hereinafter referred to as "characters") are the best means that can convey information in readable forms. When information is indicated in character forms, a relatively large area is required if the information must be provided in many different characters. If the indicating area must be limited or small, the known indicator device is practically useless.
The indicator device is usually installed on the front panel of the car, but must have its indicating area limited. There is also known a central alarm system actually installed in some types of vehicles for keeping the driver informed of the status of various functions installed through the car. As far as the known alarm system is concerned, the status of those functions should preferably be indicated by character forms which the driver can recognize as clearly as possible during the car driving. However, it is known that there are a great many instruments arranged on the front panel, and there is no space or area for installing the type of indicator which requires as many different indications as the many functions of the car. Furthermore, the known alarm system shows those locations by lighting an indicator plate on which there are provided as many indications as those locations. This makes it difficult for the driver to recognize those indications individually, and may lead to serious traffic accidents particularly when the driver gives his attention to the indicator device which shows a particular location usually indicated in small character sizes.
There is known an improved indicator which can provide many different indications within its limited indicating area. It includes a number of indicating elements formed by transparent or clear plates and superposed in layer arrangement, each of which has light reflecting spots arranged to represent a particular character and a light source on one side thereof which lights the light reflecting spots. In accordance with the indicator described above, it is possible to provide many different indications within the limited area. Therefore, it may serve as an indicator means for the central alarm system mentioned earlier. However, it has a disadvantage since it includes no means by which light sources can be checked for failure. When the indicator device is used for the alarm system, it is very important that the indicator and particularly the light sources should be checked previously before driving the car. If the inspection is made by lighting all indicating elements at a time, it makes it difficult or impossible to know which light source is wrong. In order to avoid this, therefore, the inspection must be carried out by lighting all elements one after another. Howevr, this makes the inspection work troublesome and time-consuming, resulting in overlooking some defective light sources. Because of its construction, the known indicator device has a further disadvantage: if two or more functions of the car become defective concurrently, all corresponding indicator elements are lighted at the same time, overlapping the indications indiscriminately. This is also true if two or more defective functions occur one immediately after another.